Heart Rate Zones for Training and Racing
Training Pace: In training, this range is used for long slow distance work and increases vascularization. The
pace the athlete can go in this same range increases over time as fitness and vascularization increases. The body
uses stored fat and carbohydrates (glucose in the blood stream) for its energy source. During racing, effort level
in this range ensures all caloric intake introduced can be digested, ensuring glycogen stores (carbohydrates
stored in the muscle) stay intact for later in the race.
Race Pace: In training, this pace is used for tempo work. The body continues to use fat and carbohydrates for its
energy source, though the percentage of carbohydrates used increases. During racing, the body can only digest a
percentage of the same calories the athlete can ingest at Training Pace because more blood and oxygen is
needed in the muscles for the effort level being employed. High in this zone, the athlete can generally only
digest about 50% of the calories they can digest at Training Pace. Because the athlete can only ingest a portion
of their carbohydrate needs, the remainder has to come from stored glycogen.
Hard: In training, this range is used for interval work. Above LT, the body switches to using 100%
carbohydrates for its energy source. In racing, the athlete cannot ingest additional calories as the energy source
because the stomach cannot digest it. This requires all energy needs be met from stored glycogen,
approximately 1600-2000 calories, or enough to last approximately 90 minutes to 2 hours at this effort level. If
the athlete dips into the 300 calories of glycogen stored in the liver, the body will shut down until it can recover.
The longer the athlete is racing, the more critical it becomes to manage effort level so that glycogen stores stay
intact until approximately 90 minutes are remaining in the race. In longer triathlons such as a ½ Ironman, this
means that effort level on the swim and bike has to be managed so that glycogen stores remain intact for the
final part of the run. The goal for the first two legs of the race then becomes to pace so that carbohydrate energy
needs are met through ingested calories and that the athlete begins the run with 100% of glycogen stores intact.
In an Olympic length race, the heart rate the athlete uses on the swim and bike will be determined by the
approximate length of the race, implying that most of the bike can be done at Race Pace, leaving stores so the
run can be at Race Pace and above. In a Sprint where most times are under 2 hours, the athlete can race the
majority of the race Hard because all energy needs can be met from stored glycogen. All these strategies assume
the athlete comes to the race out of taper with glycogen, hydration and electrolyte stores completely full and
that all electrolyte and hydration needs are also met during the race. If the athlete has not tapered into the race,
then the effort levels would have to be managed according to the athlete’s energy needs during the race.
The heart rates comprising the athelete’s Training Pace and Race Pace ranges will change over time as the
athlete becomes more fit.
Example using my numbers from the Olympic Center method based on blood lactate testing to show the
comparable zones for the Sally Edwards (HeartZones) method and the Joe Friel/Gale Bernhardt method:
Note: “Junk Miles” are heart rates that don’t create increases in fitness or vascularization levels.
For more information on using Heart Rates for training and racing, determining max Heart Rate, etc., see:
Overview Article on Heart Rate Training with Links